SPE-194958-MS
Operational Excellence Initiative Contributes Towards Enhanced ESP
System Reliability, Longer Run Life, and Sustained Oil Production
Hasan Jassem, Sajid Mehmood, Khaled Al-Mutairi, and Alaa Al-Shawly, Saudi Aramco
Copyright 2019, Society of Petroleum Engineers
This paper was prepared for presentation at the SPE Middle East Oil and Gas Show and Conference held in Manama, Bahrain, 18-21 March 2019.
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Abstract
Electrical Submersible Pumps (ESPs) are widely deployed means of artificial lift methods as they are
versatile and adaptable to various well conditions. However, ESP completions have significant installation
and operational costs. This paper will address an in-house developed ESP Operational Excellence (OE)
initiative that translated into longer run life, increased reliability, and sustained oil production. The objective
of this initiative is to unleash the ESPs’ full potentials, and provide structured approach to measure its
performance and sustain improvements.
The Operational Excellence model is based on asset management cycle of Plan, Do, Check, and Adjust.
Production Engineering Team with the support of Artificial Lift Specialty identified two major focus areas;
ESP turnaround, and premature failure, as OE candidates. Each focus area was examined in two parts: 1)
review of current performance, and 2) review of processes implementation. The current performance was
thoroughly reviewed and immediate actions were incorporated and tracked by Key Performance Indicators
(KPIs) and driven by results and improvements. In parallel, review of processes implementation was
conducted to fine tune current procedure and enforce Best Practices (BPs).
ESP turnaround time was significantly reduced through planning ahead required activities, desings,
and equipement. This was achieved by setting agenda and streamlined communication with all concerned
orginizations. ESP turnaround was done in 20% less days before OE. With the implementation of OE model,
oil production was ensured in timely efficient manner without comprising quality as well HSE.
The other focus area is premature failure. Once an ESP is properly designed, installed, and operated, the
ESP performance is continuously monitored and maintained. The check part of the OE cycle comes into
place when the ESP is confirmed failure. Then, the equipment is thoroughly checked using data collected
from Dismantle & Inspection Failure Analysis (DIFA) process, with the aim of enhancing performance and
deliverability. Based on the detailed investigation, the factors that affected the pump health are integrated
and adjusted for the next ESP application.
Through DIFA process management, quality assurance activities were conducted to ensure that lessons
learned during operation and maintenance, as well as improvements to existing ESP designs are incorporated
in new designs; to continuously improve ESP asset integrity and reliability. Therefore, corrective and
preventive actions were implemented to resolve common factors that affect ESP performance, such as
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downhole electrical components including motors and pumps, seals, well conditions and human error during
pump installations. By refining these factors, the ESP performance curve was improved and operational
excellence was achieved.
The implemented Operational Excellence model has shown its significance in optimizing process details
from ESP design until operation, which consequently improved ESP run life, increased reliability and
sustained oil production.
Introduction
In some oil fields, crude oil deliverability is dependent on the availability of artificial means, such as
Electrical Submersible Pumps (ESPs). Statistically, the average run life of an ESP is three years years. It's
that single piece of equipment that sometimes decides the fate of oil production because any ESP setback
directly affects crude availability from the field. "ESPs have major share in the artificial life arena for its
longevity, high flow rates, along with access to deeper zones. However, this comes with substantial costs
on both capital and operational expenditures" (Almukhtar et al 2017). Therefore, it is imperative that all
ESPs are maintained in healthy conditions and at the same time any failed ESP is returned to service in the
shortest possible time. It has been the endeavor of Production Engineering (PE) to continuously improve
upon the turnaround time of flagged ESPs in order to ensure maximum number of working ESPs. In this
regard, various measures were adopted which are going to be discussed in subsequent pages in an effort
to improve ESP reliability.
"In general, reliability of ESP is not high. In fact some studies (Dabbs and Pereira, 2007) find that the
average annual spending on maintenance for centrifugal pumps is 50% greater than for any other type of
rotating machine. ESPs may operate reliably in benign conditions but this is far from the average operating
environments in oil and gas applications (i.e. elevated temperatures and contaminated fluids). Furthermore,
ESPs are very unforgiving and prone to premature failures as a result of different factors". (Lastra et al, 2017)
At the beginning of Area-B field, ESPs maintained healthy status as expected from a brand-new
equipment. Questions were raised later in the field lifespan over health and wellness of available ESPs.
A thorough study was conducted in Area-B field that showed increasing trend of ESP issues that were
considered premature (i.e. occurred within the first 3 years since installation). Therfore, Production
Engineering along with Artificial Lift Specialty took whole responsibility to address all challenges and
ultimately reverse the trend. In fact, this was an area where challenges were seen as opportunities. "With
several factors such as: an average run life of three years of ESPs, a rig-based change-out time of up to two
weeks, and an uncertainty of when a rig can be scheduled; the need for a vigorous solution is critical for the
whole industry" (Winarno et al 2017). Operational Excellence (OE) model was introduced to govern ESP
related standards, procedure, and common practices in the mission towards efficiency, reliability, and safety.
In-House Developed ESP Operational Excellence (OE) Initiative
The Operational Excellence model is based on asset management cycle of Plan, Do, Check, and Adjust.
Once an ESP is properly designed, installed, and operated, the ESP performance is continuously monitored
and maintained. The check part of the OE cycle comes into place when the ESP is confirmed failure. Then,
the equipment is thoroughly checked, and reviewed for enhancement or adjustment if needed.
SPE-194958-MS 3
The objective of OE is to drive focus on repetitive topics and achieve results & sustainability without
compromising Health, Safety, and Environment (HSE). Through structured OE model, ESP performance
is sustained, and oil deliverability is ensured.
Production Engineering Team with the support of Artificial Lift Specialty identified two major focus
areas; ESP turnaround, and premature failure, as OE candidates.
Each focus area was examined in two parts: 1) review of current performance, and 2) review of
processes implementation. The current performance was thoroughly reviewed and immediate actions were
incorporated and tracked by Key Performance Indicators (KPIs) and driven by results and improvements.
In parallel, review of processes implementation was conducted to fine tune current procedure and
enforce Best Practices (BPs). "Throughout the previous years, ESP's have been monitored and tracked by
conventional methods; including frequent and physical well site visits, obtaining ESP related parameters,
evaluating and verifying manual charts for required course of action. Currently, all ESP's are equipped with
downhole sensors that measure intake and discharge pressures, intake and motor temperatures, vibration and
current leakage. These advanced parameters provide simultaneous ESP stamina and conditions for further
analysis" (Al Shuwaikhat et al 2017).
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1. Measures for Improving ESP Turnaround Time
A collaborative approach was adopted to replace ESPs in efficient and shortest possible manner. This effort
yielded positive results in ESP replacements and unlocking well potential. The factors which led to the
efficient turnaround time are described as under:
I. Reservoir Data For ESP Design
The process of obtaining reservoir related information was improved. For the purpose of ESP design, a
revised timeline was established to record and provide the most recent pressure and production data at
almost 1% reduced time.
II. ESP Design Time
ESP vendor was requested to avail application engineer to provide support in ESP design. The availability
of application engineer facilitated across the table discussion for the design and clarifications were provided
without resorting to lengthy communication means. This also facilitated in resolving issues if the design
deviated from given designs by Reservoir Management. Improvement in communication with ESP vendor
has 2% improved design completion time from the previous time taken before OE.
III. Equipment Availability
There was a significant improvement in availability of pump and motors for ESP replacement during
workover. This was achieved through standardization of equipment. This has facilitated the utilization of
equipment off the shelf from standardized equipment. The following steps were taken:
• Maintaining one quarter of inventory in country (for ESP string).
• Improving delivery schedule with manufacturing facility to ship at least every two weeks.
• Daily review of order status with manufacturing facility.
• Weekly meeting to update rig schedule and track design/equipment status.
• ESP Design Standardization Plan (DSP).
The implementation of above steps reduced the equipment average availability time when compared to
previous process before OE.
IV. Strip out / Remanifolding/ Well Site Clean-up Activities
Strip out and remanifolding activities are very important for timely rig mobilization. A good communication
was established to conduct stripout activities based on rig schedule. In addition, the existing resources were
boosted and additional team was availed for conducting strip out and remanifolding activities in the area.
These proactive measures has improved the time required for stripout activities from previous average of
twelve days to five days. After the rig release, the well site and the well pad is required to be returned to
original condition in order to start the remanifolding activities for putting the wells on production. Better
coordination has helped in reducing the clean-up time to almost 1% of the time taken before OE. Similarly,
post workover remanifolding activities time was also improved after the implementation of OE model. This
was also attributed to resource mobilization and close follow up activities.
V. Mobilization of Additional Rigs in Area-B field
At the beginning of 2017 only two workover rigs were operating in Area-B field to cater to workover
requirements including ESP replacements. At the beginning of July 2017, one additional rig was mobilized
in the area to speed up the ESP replacement process.
SPE-194958-MS 5
VI. Workover Operations
The workover objectives of each well were reviewed thoroughly. Since many ESP replacement jobs were
due to pre-mature failures, decision was taken to eliminate non-critical works during workover operations
without compromising on the quality of workover operations. It was agreed to eliminate running in clean
out assembly and also eliminate pressure test of the casing for the wells which were worked over in last one
year. Also, the requirement of corrosion log was eliminated for wells that were workedover in last one year
and previous log showed good casing condition. For future workover where the rig is revisiting the well
within one year, the following workover steps shall be skipped:
– Skip pressure test of casing
– Eliminate cleanout assembly run to TD
– Eliminate the requirement of corrosion log
The above process improvement has resulted in workover operations speedup and effective time
manageme of all activities and requirements. The time break of the above mentioned activities are
summarized below:
Chart-2—ESP Turnaround Enhancement
2. Proactive Measures to Address Premature Failure Issues
At the beginning of Area-B field, the number of ESP issues were insignificant. The number pre-mature
failures increased sharply in 2017. In this year, most of the failures were attributed to premature failures.
Production Engineering has adopted a proactive approach to find out the root cause of these failures
and take action accordingly. Once, ESP is confirmed failure, the equipment is thoroughly checked using
data collected from Dismantle & Inspection Failure Analysis (DIFA) process. With the aim of enhancing
performance and deliverability, the findings based on the detailed investigation of the factors that affected
the pump health are integrated and adjusted for the next ESP application.
DIFA Findings and Root Cause Analysis
The root causes of ESP failure were categorized based on the outcome of the DIFA finding. The old seal
configuration of two bags series (2BS) type attributed to 43% of the failure modes. The second major failed
component was a shorted motor model (TR5-92) (19%). Finally, the remaining contributing factors for pre-
6 SPE-194958-MS
mature failures were related to third party supplied product – Packer / WH penetrators (18%). In summary
premature ESP failures significantly affected Area-B field oil production.
ROOT CAUSES: the root causes of pre-mature ESP failures are as follows:
1. Motor and Pump Seal Failures
One of the root causes of failures was failure in seal section which was determined from the
contaminated oil discovered during DIFA. The motor (TR-5-92) was found to be substandard and
failed frequently. ESP vendor was requested not to use this type of motor in future installations in
Area-B field.
2. Wellhead Penetrator Failures
Wellhead penetrators throughout the history of Area-B field had product upgrades from generation
G-I to G-IV with engineering and design upgrades that were made to handle the continuously changing
well environment. Initially, all wells were installed with a G-I type penetrator, followed by G-II
type. 15.4% of the failures were related to the wells that were installed with G-I type penetrator. In
that regard, ESP vendor was requested to replace all wellhead penetrators G-III or older with the
latest generation (G- IV), which has greater insulation and will last longer in the presence of H2S
environment.
3. Well Conditions affecting ESP Failures
A field map was constructed to identify the areas where a sharp increase was observed in the failure
rate. The map showed that ESP failures where related to the presence of higher H2S and water cut. This
observation was also noted in recent DIFA's that had a significant effect on the penetrator terminals
(pitting corrosion), motor winding (insulation breakdown), and rotor copper end ring (discoloration)
as seen in the pictures below. "Reservoirs producing fluids with H2S present a special challenge
to ESPs. Critical ESP system materials such as copper, bronze, and elastomers will deteriorate and
fail when subject to sour environment. For example, H2S can penetrate the cable rubber and kapton
insulation, attack the copper and react to form copper sulfide. Hence, standard ESP equipment must be
upgraded to special materials and designs for successful operation is sour environment" (Al-Khalifa
et al, 2016).
4. Human Error During Pump Installation
It was found that seal oil filling practice was not uniform and human error crept in while doing the
job on rig location. Incorrect oil filling practice may result in inaccurate oil leaving the void in the seal
chamber which leads to seal failures with time. ESP vendor has now adopted a practice of conducting
an audit on rig location during ESP replacement jobs to ensure that the crew follows correct oil filling
procedure.
Action Taken to Avoid Premature Failures:
The following measures were taken to avoid premature failures:
1. Replacement of seal with new configuration (L/2BP), and improved oil filling practice on location.
This item has been implemented and currently being followed by the vendor in the field.
2. Old generation packer penetrators have been upgraded with new generation to prevent failures.
Existing penetrators were found to be weak in moderate H2S environment.
3. New chemical recipe is currently under implementation to handle well conditions such as viscous
sticky materials in the wellbore.
4. Training program and check list for field crew to avoid any human error during ESP installation.
Through DIFA process management, quality assurance activities were conducted to ensure that lessons
learned during operation and maintenance, as well as improvements to existing ESP designs are incorporated
SPE-194958-MS 7
in new designs; to continuously improve ESP asset integrity and reliability. Therefore, corrective and
preventive actions were implemented to resolve common factors that affect ESP performance, such as
downhole electrical components including motors and pumps, seals, well conditions and human error
during pump installations. By changing well condition, field service training and competency, product
manufacturing defect, application engineering experience, and third party supplied products such as
packers and wellhead penetrators, the ESP performance curve was reversed and operational excellence was
achieved.
Conclusion
Several enhancements were introduced to improve ESP performance achieve Operational Excellence, which
included:
– Improvement in ESP Design time which was achieved by better communication and across the table
discussions with vendors and other organizations.
– Enhancement in equipment availability including maintaining inventory, improved delivery from
manufacturing facilities and standardization of equipment.
– Expediting strip out/re-manifolding activities for timely mobilization of workover rigs including
deployment of additional rigs in Area-B field.
– Optimization of workover requirements such as casing pressure test, cleanout to TD and corrosion
logs in premature ESP failure wells to improve turnaround time.
Additionally, proactive measures were also adopted to minimize premature ESP failures improve up ESP
running days. These measures included:
– Replacement of seal with new configuration.
– Upgrade of packer penetrators with next generation to extend ESP run life.
– Implementation of more stringent requirement on training and field practices by ESP vendor to
enhance quality of service.
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